When I began training clients in 2008, the world of mobile fitness apps didn’t exist. Some clients would log their progress in an online journal or in an Excel spreadsheet, but that was the extent of it. Their phone was their phone; it wasn’t tracking their heart rate, measuring their movements in real-time or encouraging them to share their workout on Twitter.

We’re in a different world now. A 2014 study from research2guidance made clear that there are more than 100,000 mobile health and fitness apps. And consider this: that figure was as of the first quarter of 2014, and it was twice as many as the researchers found just two and a half years prior.

Step into a commercial gym in Anywhere, USA and you’re likely to see 25 percent of exercisers in some way using wearable tech to either guide or chart their workout. And I’d guess that 50 percent have at least one fitness app on their phone.

What does this mean for the modern-day coach and trainer? To tackle that question I think it’s important to first spend some time unpacking not the apps but the mindset of their developers.

The dramatic rise of the health and fitness app industry means increased competition. This increased competition means that those developers who want to rise above will have to better understand the science about how habits are formed. Most apps do more than just look cool and track something; they tap into the human psyche. To be competitive, they have to address our innate human suffering, our want to feel socially connected, and our need to feel rewarded.

Books such as Nir Eyal’s Hooked: How to Build Habit-Forming Products help developers do just that. Hooked boils down decades of science into a highly readable and understandable “hook model.” Essentially the book posits a strategy for how to hack the mind of a user, and do so on regular enough basis so that the product integrates itself into the user’s life and becomes a habit. This is the mindset behind any app developer worth their salt — after all, a “great product” that’s not being used is not a great product.

Most fitness apps I’ve checked out stay relevant through a four-pronged approach, each of which has potential consequences that us coaches need to be aware of.

1. They seek to inspire, among other ways, through showing the user photos of people who society would say look better than them. For men, the photos typically portray a huge and ripped man with the bodybuilder look. For women, the photos typically portray a fit but slim, even dangerously slim, woman. The models are almost always tan and glistening with sweat. These images, especially through repetitive viewing, can reinforce that the user doesn’t, in fact, look all that great. It can make them feel bad about themselves and may even cause them to shift their perception of what is normal. For some, this may inspire by the vehicle of a temporary lowering of self-esteem.

The Consequence: We’ve all been there; we’ve hung up posters or held someone up as the model for what we hoped to look like. But the consequence here is that these images are with our clients 24/7. They may be viewing them before they walk into the gym and in between sets for an extra boost of inspiration (often through the aforementioned lowering of self-esteem).

The Answer: It’s important to use positive reinforcement beyond your client’s body image. For many new trainers, looks are the easy thing to compliment, especially when a client has been open to you about wanting to change in this regard. But do not make these compliments on body image become your go-to habit. Find improvements in form, attitude, and consistency. Compliment your client their work-life balance, or even their personality.

2. They use gamification. Users can receive points, badges, or icons and can compete against themselves, friends, and/or anyone else in the world who has the app. While this can certainly be a fun way to keep track of progress and encourage consistency, gamification can shift the attention away from training in order to achieve a greater PR, for enjoyment, or for better health, and place the emphasis on training for the sake of beating others within the game of the app.

The Consequence: When the app doesn’t work, is no longer updated or simply no longer feels like fun, the client may feel an immense sense of loss. They may not feel motivated to workout whatsoever.

The Answer: I’ve found clients to be quite dug in on this. While fitness as a game can certainly help develop consistency, it’s important to both provide your own rewards as well as to encourage your clients to find their own. If you’re a personal trainer, for example, this can include a 2-sessions free card after your client completes 10. And to help their own pursuit, ask them how they plan to celebrate once they hit a particular goal.

3. They make social sharing easier. In some apps, as soon as you check into your gym it automatically posts to your Twitter and Facebook accounts. Others can even do this with each set you complete. This is a win for the app developer because the user is essentially publicly endorsing their product through each use, but it can also skew the balance of motivation by shifting the focus almost purely on an extrinsic reward.

The Consequence: Many users have reported being cyberbullied for what statistics were posted to social media, but I think the primary consequence here is, as with gamification, it can shift the focus away from internal motivation and towards external motivation. Again, this could mean a bad response on Twitter (or an app failure) causes your client to feel entirely unmotivated.

The Answer: As with the answer in relation to images, it’s important here to help your client find their reason for working out. It’s also important to help them nurture perhaps more sustainable reasons. For example, even if they came to you to look better for their wife/husband, provide compliments on how they really seem to enjoy the process. You might even mention the many studies that prove how regular exercise can improve their sense of wellbeing.

4. They have a built-in sense of community. Even if the user shares on Twitter, the best apps I’ve tried allow you to have a sense of community with the other users of the app. Here, users are able to encourage each other, “like” certain routines, ask questions, and receive advice. While the sense of community has clear benefits, especially for the exerciser who typically works out alone, a reliance on this community can sometimes have a negative impact.

The Consequence: As with everything above, if the app goes down, so too may your client’s motivation. Also, using this community in lieu of seeking sustainable internal motivation factors and/or professional advice could demotivate the client and even be dangerous for their health.

The Answer: Do your best to be their source for professional advice. This includes not only knowing what you should know as a trainer, but letting them know that you know of the apps as well. They need to know you’re up on the times, the latest research, and the tools they may be using. This will ensure they turn to you first, and the app second.

In conclusion, modern coaches and trainers need to pair the old school with the new school. Many of the apps out there are phenomenal, and can do things we never thought possible, even five years ago. Maximize their use, but understand their consequences and be sure to take time to discuss the consequences with your clients as well. This will help create a more sustainable practice, and likely a deeper relationship between you and your client.